Global Precipitation Measurement data compared to ground based disdrometer measurements

Abstract

Additional thesis - Rapid advancements in satellite observation technologies have resulted in an unprecedented availability of remotely sensed rainfall characteristics. These freely available precipitation measurements could be of great value for improving current weather prediction, particularly in developing countries where other data is scarce. A key parameter to derive rainfall intensities is the drop size distribution (DSD). Data of the Global Precipitation Measurement (GPM) mission provides amongst others the DSD and rainfall intensity, but it is unknown how well the device can convert the DSD to rain intensity. Therefore the main goal of this study is validating the GPM measurement results, by using ground based disdrometers. The disdrometers were located in De Bilt (The Netherlands), Yangon and Bago (Myanmar). In the Netherlands an industrial standard Thies LPM was used, whereas in Myanmar innovative Delft-disdrometers were tested. DSD’s obtained from the Thies LPM showed a decreasing peak for increasing rainfall intensities, which corresponds to DSD theory. In most cases the DSD’s of the Thies LPM and GPM were comparable with an average R2 of 0.9. On the other hand, the rainfall intensities for these two datasets were not comparable with a relative error varying between 49 and 3314 %. The very limited joint occurrence of satellite flyover and rain events caused insufficient data for validation in Myanmar. The data obtained from the Delft-disdrometer in Yangon showed that, despite the limitations of this innovative device, it is possible to produce representative DSD.